How to Change the Sand in Your Sand Filter

May 15, 2015 at 12:48 PM

Zodiac welcomes Matt Giovanisci from Swim University as he walks our readers through a simple step-by-step guide to changing the sand in a swimming pool's sand filter and teaches how to properly remove the sand, add new sand, backwash the filter and get your pool running smoothly.

A general rule of thumb is to change the sand in your sand filter once every 3 to 5 years. Over time the sand loses its coarseness and becomes smooth and round, which makes it harder for the sand to trap smaller particles.

The first step in changing the sand is to create a checklist of the things you’ll need, which are:

Next, make sure there is no water going to your filter and remove the drain plug from your tank. It may take some time for your filter to completely drain, depending on the size of your tank.

Remove the clamp or collar that holds the multiport valve in place. Then, remove the hoses or pipes attached to the valve. If your filter is hard-plumbed with PVC, you will need to cut the pipes and install two unions, so you won’t have to cut the pipes each time you need to replace the sand.
Now, remove the multiport valve from the filter by twisting slightly and pulling upwards. Be very gentle while doing this step. The valve is attached to a standpipe that runs into the sand. At the bottom of the standpipe there are laterals that can easily be damaged under the weight of the sand.

Before you remove and add new sand, make sure you use duct tape or a rubber plug to block the opening of the standpipe inside the filter. You don’t want sand getting inside the standpipe, because when you start the filter, it will end up in your pool.
Remove the sand by using a shop vac or plastic cup. The bigger the filter, the longer it will take. I suggest using a shop vac to speed up the process.
Fill the tank halfway full of water before adding the new sand. This will protect the laterals, at the bottom of the standpipe, from being damaged once you start adding the heavy sand.

Now, add each bag of sand to the filter, making sure the standpipe is centered and properly seated.
Once you’ve added all the sand, replace the multiport valve and connect the hoses or pipes to the valve.
Before you start your filter system, turn your multiport valve to Backwash and let it run for two minutes. Then, shut the pump off and turn your valve to Rinse. Let it run for one minute. Now, you can turn your multiport valve to filter and you’ve completed your task!

Matt Giovanisci is the creator of Swim University, an online guide to swimming pool care. He has over 15 years of experience in the swimming pool and hot tub industry. He is also an award winning web designer and has been featured on "Martha Stewart Radio" as a pool and spa expert.

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